Scroller Spyer

Scroller.js

var Scroller = {
	registeredHandlers: [],
	install: function(opt) {
		Scroller.registeredHandlers.push(opt);
	},
	onScroll: function(){
		var now = window.scrollY;
		$.each(Scroller.registeredHandlers, function(){

			if (this.after) {
				if (now>=this.after) {
					if (!this.permanentAfter || !this.afterYet){
						this.afterYet = true;
						if (this.cb) this.cb(true);
						if (this.el) this.el.addClass(this.customClass?this.customClass:'on');
					}
				} else {
					if (!this.permanentAfter) {
						if (this.cb) this.cb(false);
						if (this.el) this.el.removeClass(this.customClass?this.customClass:'on');
					}
				}
			}

			if (this.between) {
				if (now>=this.between[0] && now<=this.between[1]) {
					if (this.cb) this.cb(true);
					if (this.el && !this.el.hasClass(this.customClass?this.customClass:'on')) {
						this.el.addClass(this.customClass?this.customClass:'on');
					}
				} else {
					if (this.cb) this.cb(false);
					if (this.el && this.el.hasClass(this.customClass?this.customClass:'on')) {
						this.el.removeClass(this.customClass?this.customClass:'on');
					}
				}
			}

			if (this.event) {
				this.event();
			}

		});
	},
	init: function(){
		$(window).scroll(Scroller.onScroll);
		Scroller.onScroll();
	}
};